QEMSCANQuantitative Evaluation of Minerals by Scanning Electron Microscopy

Applications

•Mineral Processing•Economic Geology•Geometallurgy•Hydrometallurgy•Pyrometallurgy•Oil and Gas•Forensics...

QEMSCAN measurement types

•Bulk Mineralogical Analysis (BMA) – rapid line scan analysis to obtain good statistics on bulk mineralogy

•Particle Mineralogical Analysis (PMA) – detailed particle min-eralogical information

•Specific Mineral Search (SMS) – detailed particle mineralogical information on only specific minerals of interest (e.g. sulfides)

•Trace Mineral Search (TMS) – detailed particle mineralogical information on trace mineral phases (e.g. Au, PGMs)

•Field scan – detailed mapping of larger samples (e.g. thin sec-tion, drill core)

Information obtained from QEMSCAN

•Bulk mineralogy of samples•Element deportment•Ore characterisation•Particle properties (e.g. grain and particle size

and shape) •Particle images •Mineral liberation•Mineral association•Theoretical grade recovery curve

This equipment was financially supported by the Department of Science and Technology in partnership with the National Research Foundation, South Africa, 2014

What is QEMSCAN?

QEMSCAN is the state of the art, top of the range automated mineral analyser. It is an analytical tool which provides rapid, reproducible and statistically reliable quantitative information on minerals and certain man-made materials for a variety of disciplines. This tool has been custom developed for the mining industry.

QEMSCAN 650F utilises:•Field emission gun-scanning electron microscope (FEG-SEM)•High resolution back scattered electron (BSE) detectors•State-of-the-art energy dispersive x-ray spectroscopy (EDS) detectors•Spectral analysis engine

Analysed phases are classified as specific minerals according to their BSE and chemical composition compared to that within a user developed, reference mineral library known as a SIP file (Species Identification Protocol). A detailed database of statistically representative mineralogical information is built up, which is later interrogated by the user.

Fe Cu

S

O

SiS

Fe

1. Polished grain mount 2. Particles are examined in pre-defined ‘fields’ 3. A particle is distinguished from the back-ground using a BSE threshold brightness

4. Each particle is split into a pre-defined grid of pixels, each with an x-ray analysis point

5. Pixels are assigned an identity using the species identification protocol

Left: SIP entry for the mineral chalcopyrite

6. A false colour map is created for each particle; each colour represents a miner-alogy or chemical grouping. Quantitative data is also produced.

QEMSCAN 650F (right) and sample block holder with

30mm sample disks (left)

How does the QEMSCAN work?

ccp

qtz

py

Left: schematic showing the difference between BMA and PMA

analysis

75 microns

QuartzMicaChloritePyriteFeldspar

BMA

75 microns

QuartzMicaChloritePyriteFeldspar

PMA